A procedure to study human operant conditioning is described using a timeout from a high-force requirement as reinforcer when a high force response was required. Experiment 1 reported evidence that a timeout from a high-force requirement acted as a reinforcer and a second experiment demonstrated sensitivity to delay to escape from the force requirement as a parameter of choice in a self-control paradigm. The results of the two experiments indicate a functional similarity between unconditioned reinforcers (e.g., food) used in nonhuman subjects and the present reinforcer, demonstrating that the present procedure is well-suited to study operant conditioning in humans.